Novel c-16,17 spiro-orthoester steroids and preparation

ABSTRACT

C-16,17 SPIRO-ORTHOESTRS AND METHOD OF PREPARATION INVOLVING REACTING A 16,17-DIHYDROXY STEROID WITH AN OALKYL ALKANOIC ACID LACTONIUM TETRAFLUOROBORATE IN THE PRESENCE OF A BASE. THE NOVEL SPIRO-ORTHOESTERS ARE USEFUL ANTIINFLAMMATORY AGENTS.

3,798,217 NOVEL C-16,17 SPIRO-ORTHOESTER STEROIDS AND PREPARATION Jack Ackrell, Norfolk,England, and John A. Edwards,

Los Altos, and John H. Fried, Palo Alto, Calif., assignors to Syntex Corporation, Apartado, Panama No Drawing. Continuation-impart of application Ser. No. 37,292, May 14, 1970, now Patent No. 3,716,529. This application Aug. 11, 1972, Ser. No. 279,755

Int. Cl. C07c 173/00 US. or. 260-23955 D 5 Claims ABSTRACT OF THE DISCLOSURE C-16,17 spiro-orthoesters and method of preparation involving reacting a 16,17-dihydroxy steroid with an alkyl alkanoic acid lactonium tetrafluoroborate in the presence of a base. The novel spiro-orthoesters are useful antiinfiammatory agents.

This is a continuation-in-part of application Ser. No. 37,292, filed May 14, 1970, now US. Pat. 3,716,529.

This invention relates to novel 16,17-spiro-orthoester steroids in the corticoid series and to a novel process for preparing these compounds using an O-alkyl alkanoic acid lactonium tetrafluoroborate in the presence of a base.

The 16,17-spiro-orthoester corticoid steroids of the present invention can be represented by the following general Formulas A and B:

CHz-R wherein, in each applicable formula,

R is hydrogen, hydroxy, fluoro, chloro, bromo, .alkoxy, phenyloxy, or carboxylic acylorry of less thanJZ carbonatoms; R is hydrogen fluoro, chloro, bromo, or methyl; R is hydrogen, chloro, fluoro, or bromo; R is oxygen or the group in which R is hydroxy or, (when R is bromo or chloro), bromo, chloro or fluoro; each Z is a carbon-carbon single bond or a carbon-carbon double bond; and' n is the positive integer1,2,3, 'or 4.

United States Patent 'ice Particularly'preferred are those compounds of Formulas A and B in which R is hydroxy, chloro, or fluoro, R is fluoro, R is chloro, and R is the group in whichR is chloro.

The novel 16,17-spiro-orthoester corticoids of the present invention possess anti-inflammatory and glucocorticoid activity. Accordingly, the present compounds are usefulin the treatment of allergic diseases, collagen diseases, skin diseases, and the like. In this usage, the compounds of the present invention are administered and used in the same manner as other corticoid steroid anti-inflammatory agents, such as fluocinolone acetonide.

The process of the present invention for preparing the compounds of the present invention of Formulas A and B above comprises reacting the corresponding 160:,17a-dihydroxy steroid with an O-alkyl alkanoic acid lactonium tetrafluoroborate in the presence of base.

The Q-alkyl alkanoic acid lactonium tetrafluoroborate reagent is prepared by reacting together a trialkoxonium tetrafluoroborate and an alkanoic acid lactone of 4 to 7 carbon atoms.

In the present invention, the useful alkanoic acid lactones of 4 to 7 carbon atoms are butyric acid lactone, pentanoic acid lactone, hexanoic acid lactone, and heptanoic acid lactone.

In the present invention, suitable trialkoxonium tetrafluoroborates include those known in the art, preferably the lower alkyl compounds, such as trimethyloxoniurn tetrafiuoroborate, triethyloxonium tetrafluoroborate, tripropyloxonium tetrafluoroborate, and the like.

In the present invention, suitable bases include ammonia; primary alkylarnines, e.g. methylamine, ethylamine, isopropylamine, n propylamine, and the like; secondary alkylamines, e.g., dimethylamine, diethylamine, methylpropylamine, and the like; trialkylamines, e.g. trimethylamine, triethylamine, and the like; and monocyclic heterocyclic amines, e.g., pyridine, collidine, piperidine, morpholine, and the like,

The principal reaction hereof is conducted by reacting together a 16,17-dihydroxy starting steroid with the 0- alkyl alkanoic acid lactonium tetrafluoroborate, preferably in liquid inert organic reaction media. The reaction is conducted at temperatures ranging from about 0 to about 30 and for a period of time suflicient to complete the reaction ranging from about Sminutes to about 1-5 hours. In the practice of this process, the reactions are contacted and maintained in any convenient order or fashion preferably within the given temperature range. After thereaction, the product is separated and isolated from the reaction mixture by any of the -usual and conventional techniques such as evaporation, filtration, decantation, ex traction, chromatography, and the like.

Suitable liquid inert organic reaction media in the present invention include those usually employed in organic reactions such as aromatics, e.g. benzene, toluene; ethers e.g. dioxane, diethylether, and the like; and, preferably, the halogenated hydrocarbons, e.g., chloroform, methylene chloride, carbon tetrachloride, 1,2-dichloroethane, 1,1-dichloroethane, and the like; either individually or mixtures thereof.

.The reaction consumes the reactants on the basis of one equivalent of the 16a,17u-dihydroxy steroid per equivalent of the O-alkyl alkanoic acid lactonium tetrafluoroborate per equivalent of base. However, the relative amounts of the reactants employed are not critical, some of the desired product being prepared when employing any proportions thereof. In the preferred embodiments,

,, from 1 to about 5 equivalents of each of the O-alkyl alkanoic acid lactonium tetrafiuoroborate and base are steroid.

The O-alkyl alkanoic acid lactonium tetrafluoroborate is prepared by reacting together a trialkyloxonium tetrafluoroborate and an alkanoic acid lactone, preferably in liquid inert organic reaction media at from about to about 20 C. and for from about '24 to 48 hours. This method is more completely described in Ber. 89, 2060 (1965), which is hereby incorporated by reference.

The process of the present invention and the process for preparing the O-alkyl alkanoic acid lactonium tetrafluoroborate are each, in the preferred embodiments, conducted under anhydrous conditions.

The process of the present invention can be practiced upon starting materials bearing the substituents defined by each of R (when other than hydroxy), R R R and Z. The starting 16oz,17a-dihydroxy compounds are known and can be prepared in accordance with known proce duressee U.S. Pats. 3,048,581 and 3,053,838. If necessary, starting materials not containing a 16a hydroxy group can be incubated with Streptomyces 'r oseo'chro mogrtus in accordance with the procedure known per se in the art. In the alternative manner, the corresponding known 16a,17ot-3.C6t0flid compounds can be cleaved with acid in accordance with the procedure known per se' in the art. The 16a,17a acetonide starting compounds are also useful for preparing the corresponding 21-alkoxy and phenyloxy ethers with subsequent cleavage of the 1611,1702- acetonide group. The etherification at 'C-21 of the 16a, 17a-acetonide compounds is conducted by treating the corresponding 21-hydroxy compounds with silver oxide and an alkyl halide or phenyl halide in an inert organic solvent at a temperature from 0 C. to the reflux temperature of the reaction mixture, as set forth in U.S. patent applica tion Ser. No. 822,049 filed May 5, 1969, by Berkoz, Cross, Edwards, and Fried for Steroid Ethers, now abandoned, the discussion of this method of which application is hereby incorporated by reference.

Alternatively, the molecular substituents can be introduced after the principal reaction hereof, if more suitable from a chemical standpoint. One exception to this is the generation of the 9,11-fluorohydrin group which is'best introduced prior to the preparation of the orthoester product.

The C-21 esters can be used as a protecting group when it is desired to prepare a 21-hydroxy final product, the ester being conventionally base hydrolyzed after the principal reaction hereof. p

The following preparation and examples further illus-' trate the manner by which the present invention can be practiced and represent, in one aspect, the best mode for carrying out the invention. As such, however, they should be construed merely as illustrative and not as limitative upon the overall scope hereof.

PREPARATION 1 One gram of triethyloxonium tetrafluoroborate is dis persed in 5 rnl. of dry methylene chloride under anitrogen atmosphere. To the resultant mixture is added 0.45 ml. of butyric acid lactone while maintaining the anhydrous conditions. The resultant mixture is allowed to stand overnight at room temperature to provide a solution of O-ethyl butyric acid lactonium tetrafluoroborate.

In accordance with the foregoing procedure, the alkanoic acid lactones listed in Column A below are reacted with the trialkyloxonium tetrafluoroborates listed in 601- umn B below to provide the respective reagents listed under ColumnCbelow.

Column A:

butyric acid lactone pentanoic acid lactone hexanoic acid lactone heptanoic acid lactone employed per equivalent of l6a,l7a -dihydroxy starting 'trirnethyloxoniur'n' tetrafluoroborate" triethyloxonium tetrafluoroborate tri-n-propyloxonium tetrafluoroborate ColumnCn. O-inethyl butyric acid lactonium tetrafluoroborate .O-ethyl butyric acid lactonium tetrafluoroborate v Q-n-propyl butyric acid lactonium tetrafluoroborate Q methyl pentanoic acid lactonium tetrafluoroborate O-ethyl pentanoic acid-lactonium tetrafluoroborate. .,borate- H 2- 1 Y O-n-propyl peritanoic acid"lactoniurnltetrafiuoroborate r v O-methyl hexanoic acid lactonium tetrafluoroborate O-ethyl hexanoic acid lactonium tetrafluoroborate O-n-propyl hexanoic acid-hexanoic acid lactonium tetrafluoroborate i i -O-rnethylheptanoic acid lactonium tetrafluoroborate O-ethyl heptanoic acid lactonium tetrafluoroborate O-n-propyl heptanoic acid lactonium tetrafiuoroborate 1 EXAMPLE 1 6m fiuoro 911,115 -dichloro J 21 acetoxypregna; 1,4- diene-16a,17a diol-3;20-dione (1-15 mg.) is dispersed in 4.5 ml. of dry methylene chloride containing 50 mg. .of dry'triethylamine. To the resultant'mixture is added 0.4

-. ml. of. the O-ethyl butyric acid lactonium tetrafluoroborate solution prepared in Preparation 1 in a dropwise fashion and at room temperature with stirring over a periodof 10 minutes. The resultant mixtureis then filtered throughia column of alumina and then crystallized to yield the 6ocfi11OIO-9oc,llfi-(lichlOIO-16a,17oc0XOlaI1- 2',2' ylidenedioxyl 21 acetoxypregna 1,4 diene-3, 20-dione.

EXAMPLE 2 602,90: difluoro 21 chloropregna; '1-',4 diene 11 8, 16fl,17a-triol'-3, 20-dione(100 mg. is dispersed in 10 ml. of dry methylene chloride containing mg. of dry trimethylamine. To the resultant solution is then added 0.4 ml. of the O-ethylbutyric acid lactonium tetrafluoroborate solution prepared in Preparation 1 in a-dropwise fashion and at room temperature with stirringovera period of 10 minutes. The resultant reaction mixture is then filtered through a column of alumina and subjected to preparative thin layer chromatography to provide the 6a,9a-difluorodenedioxy-2l-acetoxypregna-1,4-dien- 1113-01 3,20-dione product.

EXAMPLE 4' 6,6-difluoro-2l-acetoxypregna 1,4-diene-11 3,16u,17atriol-3,20-dione (150 mg.) is dispersed in 15 m1. of chloroform containing 100 mg. of methylamine at room temperature and with stirring. To the resultant mixture is added 0.5 ml. of a solution of O -methyl pentanoic acid lactonium tetrafluoroborate, as'pr'epared in Preparation 1, in a dropwise fashion over a period of 25 minutes at .spectively.

room temperatureand with stirring. After the-addition,

the reaction mixture is filtered through a column of alumina and subjected to preparative thin layer chromatography to provide the 6,6-diflul0-160:,17oz-OX311-2',

2-ylidenedioxy-2l-acetoxypregna 1,4 dien-1l5-ol-3,20-

dione product. EXAMPLE The procedure of Example 3 is repeated using, in lieu of O-ethyl butyric' acid lactonium tetrafluoroborate reagent, each of O-ethyl hexanoic acid lactonium tetrafluoroborate and O-ethyl heptanoic acid lactonium tetrafluoroborate to provide 6u,9a-difiuoro-l6a,l7a-oxepan- 2',2-y1idenedioxy-21 acetoxypregna-l,4-dien-115-01-3, 20-dione and 6m,9a-difluoro-16a,17u-oxocan-2',2-ylidenedioxy-Zl-acetoxypregna 1,4-dien-115-0l-3,20-dione re- EXAMPLE 6 To a solution of l g. of 6a,9a-difluor0-l6a,l7a-oxolan- 2,2'-ylidenedioxy 21-acetoxypregna-1,4-dien 115-01-3, 20-dione in 50 ml. of methanolis left for 3 hours with a 5% solution of potassium hydroxide in ml. of water at 0 under nitrogen. The reaction mixture is then,poured into ice water and the solid which forms is collected by filtration, washed with water to neutrality and dried to yield 60:,9u-diflll0l'0-160:,17or-0X0l21Il-2', '-ylidenedi0xy pregna-l,4-dien-115,21-diol-3,20-dioine which is recrystallized from methylene chloridezether.

In like manner, the foregoing hydrolysis procedure can be utilized to prepare the other l6a,l7a-spiro-ortho ester products hereof containing a 21-hydroxyl.

EXAMPLE 7 The procedures of Examples 1, 2, 3, and 4 are repeated utilizing, in lieu of the inert liquid organic reaction media used therein, the inert liquid organic reaction media set forth in Column D below, and, in addition, utilizing, in lieu of the amine used in these examples, those amines set forth in Column E below, with similar results in each instance.

Column D:

carbon tetrachloride chloromethane diethyl ether dioxane toluene mesitylene Column E:

ethyl amine di-n-propyl amine isopropyl amine pyrdine collidine Similarly, the foregoing modifications, when employed at a temperature of 0, affords similar results in each instance.

EXAMPLE 8 The procedures of Examples 1 and 2 are repeated employing, in lieu of O-ethyl butyric acid lactonium tetra-fluoroborate, O-methyl pentanoic acid lactonium tetrafluoroborate to provide the 6a-fluoro-9m,115-dichloro-l6a,l7u-oxan-2',2' ylidenedioxy-Zl-acetoxypregna-l, 4-diene-3,20-dione and 606,9a-dlfll1010-16u,17oL-OXan-2',2'- ylidenedioxy-Z1-chloropregna1,4-dien 1l5-ol-3,20-dione products, respectively.

EXAMPLES 9 TO 37 In accordance with the foregoing procedures, the following products are prepared by reacting the corresponding 16a,l7a-dihydroxy starting steroid with the appropriate :O-alkyl alkanoic acid lactonium tetrafluoroborate reagent.

16a, l7a-oxolan-2',2'-ylidenedioxypregna-Lene-S,1 1,

21-trione,

16m,17a-oxolan-2,2-ylidenedioxypregna-1,4-diene- 1 15,2l-diol-3 ,20-dione,

16a,17a-oxan2',2-ylidenedioxypregna-1,4-diene-1 l 5,

21-diol-3,20-dione,

16a,17a-oxolan-2',2'-ylidenedioxy-2l-acetoxypregna- 1,4-dien-l l5-ol-3,20-dione,

16a,17u-oxepan-2',2-ylidenedioxy-2l-acetoxypregna- 1,4-dien-l 15-ol-3,20-dione,

6a-methyl-16a,17m-oxan-2,2-ylidenedioxy-2l-chloropregna-4,6-dien-1 l5-ol-3,20-dione, pregna-l,4,6-triene-3,20-dione,

90:,1 15,21-trichloro-16a,l7u-oxepan-2',2'-ylidenedioxypregna-1,4'-diene-3 ,20-dione,

6u,9a-difluoro-16a,17m-oxolan-2',2'-ylidenedioxypregna- 4-en-115-ol-3,20-dione,

16 a, 17 a-oxan-2',2'-ylidenedioxy-2l-methoxypregna- 1,4-dien-1l5-ol-3,20-dione,

6a-methyl-9a, 1 15-dichloro-16a, l7a-oxepan-2',2'-ylidenedioxy-Z1-phenyloxypregna-4,6-diene-3,ZO-dione,

Got-chloro-16a,17cr-oxolan-2',2-ylidenedioxypregn-4- ene-l 15,21-diol-3,20-di0ne,

9oz,1 lfl-dibromo-16a,17a-oxan-2',2-ylidenedioxy-21- acetoxypregna-4,6-diene-3,20-dione,

6a,9a,1 15-tribromo-16a,l7a-oxepan-2,2'-ylidenedioxypregn-4-en-21-ol-3 ,20-dione,

16a,17a-oxocan-2',2-ylidenedioxy-2l-bromopregna-l,4

dien-l 15-01-3 ,20-dione,

dioxypregnal ,4-diene-3,20-dione,

6oc-fl11OI0-9a,1 15-dichloro-16a,17a-oxan-2',2'-ylidene dioxypregna- 1,4-dien-2 1-ol-3 ,20-dione,

6,6-difiuoro-l6a,17a-oxo1an-2',2'-ylidenedioxypregn-4- ene-3,1 1,20-trione,

6,6-difluoro-16a,17a-oxolan-2',2'-ylidenedioxypregna-1,4-

diene-l 15,2 l-diol-3,20-dione,

6,6-difluoro-l6a,17u-oxan-2',2'-ylidenedioxypregna-1,4-

diene-l 15,21-diol-3,20-dione,

6,6-difiuoro-l6a,17a-oxolan-2,2'-ylidenedioxy-21- acetoxypregna- 1,4-dien-1 l 5-ol-3,20-dione,

6,6-difluoro-16a,17u-oxepan-2,2'-ylidenedioxy-2l-acetoxypregna- 1 ,4-dien-1 l5-ol-3,20dione,

6,6,21-t1ifll101'0-16cz, 17a-oxocan-2,2'-ylidenedioxypregna- 1,4-dien--ol-3,20-dione, and

6,6,9a,21-tetrafluoro-l6a, l7a-oxan-2',2-ylidenedioxypregn-4-ene-3 ,l 1,20-trione.

6a-fluoro-9a,l 1 3-diChlOIO-16or, l7a-oxolan-2',2'-ylidenedioxy-Zl-acetoxypregna-1,4-diene-3 ,ZO-dione,

6,6-diflu0r0-9a,l l5-dichloro-16a, l7a-oxolan-2,2-

ylidenedioxy-2 l-acetoxypregnal ,4-diene-3,20-dione,

6,6,9a-trichloro-16a,17a-oxolan-2,2-ylidenedioxy-21- chloropregnal ,4-dien-1 15-ol-3,20-dione,

6,6,9a-trifiuoro-16a,l7a-oxolan-2,2-ylidenedioxy-2lacetoxypregna-l,4-dien-115-0l-3,20-dione,

6,6-CliflUOIO-9a,l l5-dichloro- 1 6a, 1 7a-oxolan-2',2'-ylidenedioxypregna-l ,4-dien-21-ol-3,20-dione,

6,6-difluoro-9a,l 15,2l-trichloro-16u,l7a-oxolan-2',2-

ylidenedioxypregnal ,4-diene-3,20-dione,

6,6,2 l-iIifllJOIO-Qoz, l l 5-dichloro- 1 6a, l7a-oxolan-2',2'-

ylidenedioxypregna-1,4-diene-3,20-dione.

What is claimed is: 1. In the process for preparing a compound according to the Formulas A and B:

C I-B "-0 CHt( 2)n 8 R is hydrogen, chloro, fluoro, or bromo; R is oxygen or the group in which R is hydroxy or, (when R is bromo or chloro) bromo, chloro, or fluoro; each Z is a carbon-carbon single bond or a carbon-carbon double bond; and n is the positive integer 1, 2, 3, or 4, the step which comprises reacting a 16a,17a-dihydroxy steroid with an O-alkyl alkanoic acid lactonium tetrafluoroborate in the presence of base.

2. The process according to claim 1 wherein said base is selected from triethylamine, trimethylamine, and methylamine.

3. The process according to claim 2 conducted at from about 0 C. to about 30 C. and in liquid inert organic reaction medium.

4. The process according to claim 3 wherein said 0- alkyl alkanoic acid lactonium tetrafluoroborate is o-ethyl butyric acid lactonium tetrafiuoroborate.

5. The process according to claim 4 wherein said base is triethylamine.

References Cited UNITED STATES PATENTS 3,073,743 1/1963 Spero 16765 3,073,817 1/1963 Diassi et al. 260-239.55 3,174,971 3/1965 Krakower et al. 260-23955 3,338,926 8/1967 Alvarez et al 260397.4

HENRY A. FRENCH, Primary Examiner US. Cl. X.R. 260-999 

